Modified alginate-like adsorbing material and preparation method thereof

Abstract

The application provides a modified alginate-like adsorption material and a preparation method thereof, and relates to the technical field of wastewater treatment. The modified alginate-like adsorption material comprises an alginate-like matrix and a functional group connected to the alginate-like matrix; and the functional group comprises a carboxyl group and an amino group. The preparation method of the modified alginate-like adsorption material comprises the following steps: mixing raw materials containing alginate, an amino-containing polymer and an alcohol solvent, performing solid-liquid separation, and obtaining a solid product; and performing a cross-linking reaction on the solid product and a cross-linking agent to obtain the modified alginate-like adsorption material. According to the application, the amino-containing polymer is grafted into the alginate through a chemical bond to prepare a modified alginate-like adsorption material, the adsorption efficiency of the modified alginate-like adsorption material on heavy metal ions is improved, and the adsorption effect on Cu(II) is significantly improved, which widens the road for potential high-value application of alginate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a modified alginate-like adsorption material and a preparation method thereof. BACKGROUND

[0002] Since alginate-like extract (ALE) was extracted from aerobic granular sludge, researches on ALE have been extensive. According to the unique properties of alginate-like extract, it has been used as a flame retardant, a cement conditioner and a waterproof coating, etc. However, most of the current researches are mainly based on the extraction of aerobic granular sludge, and there are few researches on ordinary activated sludge. In fact, the yield of ordinary activated sludge in sewage treatment is huge, and the extraction and application of ALE in ordinary activated sludge have great prospects.

[0003] ALE contains a large number of negative functional groups and has the potential to bind with metal ions. However, the gel performance of ALE extracted from activated sludge is weaker than that of commercial alginate, and the active sites of ALE may be less than those of commercial alginate. Therefore, if ALE is simply used to adsorb and bind divalent metals, the formed gel is too loose, and it is difficult to effectively recover the adsorbent, especially when adsorbing low-concentration metals. In view of this problem, it is urgent to find a new adsorbent that can adsorb low-concentration metals and be effectively recovered. We use PEI to cross-link and modify ALE. Previous studies have shown that PEI can improve the adsorption performance of nanocellulose microcrystals for heavy metals. After PEI modification, more active adsorption sites and amino groups are introduced on the main carbon chain, which, together with the original functional groups, enhances the adsorption efficiency of heavy metals and further improves the strength of ALE and the recovery effect. SUMMARY

[0004] The present application aims to provide a modified alginate-like adsorption material and a preparation method thereof. By cross-linking and modifying alginate-like extract extracted from sludge, a new heavy metal adsorbent is prepared, and the adsorption effect of Cu(II) is significantly improved, which provides a possible direction for the potential high-value application of alginate-like extract.

[0005] To achieve the above purpose, the technical scheme of the present application is as follows:

[0006] The present application provides a modified alginate-like adsorption material, which comprises: an alginate-like matrix and a functional group connected to the alginate-like matrix.

[0007] The functional group comprises a carboxyl group and an amino group.

[0008] Preferably, the modified alginate-like adsorption material has a three-dimensional network cavity structure, and the particle size is 200nm-300nm.

[0009] Preferably, the alginate-based matrix comprises alginate material extracted from sludge.

[0010] The application also provides a preparation method of the modified alginate adsorption material, comprising:

[0011] mixing raw materials including alginate, amino-containing polymer and alcohol solvent, solid-liquid separation to obtain a solid product;

[0012] cross-linking reaction of the solid product with a cross-linking agent to obtain the modified alginate adsorption material.

[0013] Preferably, the preparation method satisfies at least one of the following conditions:

[0014] a. the particle size of the alginate is 2-20 μm;

[0015] b. the amino-containing polymer comprises at least one of polyethylene imine, polyacetamide and polyacrylimine;

[0016] c. the alcohol solvent comprises at least one of methanol, ethanol, propanol and isopropanol;

[0017] d. the cross-linking agent comprises glutaraldehyde;

[0018] e. the solid-liquid separation comprises centrifugation at a speed of 5000-10000 rpm for 15-30 min.

[0019] Preferably, the cross-linking reaction comprises transferring the solid product into water, adjusting pH to 8-9, dropwise adding the cross-linking agent, continuously stirring to obtain the modified alginate adsorption material.

[0020] Further preferably, the cross-linking reaction satisfies at least one of the following conditions:

[0021] f. the cross-linking agent is selected from glutaraldehyde with a mass fraction of 20-30%;

[0022] g. the volume ratio of the water to the alcohol solvent is 1:(0.9-1.1), and the volume ratio of the cross-linking agent to the water is 1:(20-30);

[0023] h. the adjusting of pH to 8-9 comprises using sodium hydroxide solution;

[0024] i. the time of the continuous stirring is 1-2 h;

[0025] j. After the cross-linking reaction is completed, the continuously stirred mixed solution is further centrifuged, washed, and dried to obtain the modified alginate adsorption material.

[0026] Preferably, the preparation method of the alginate comprises:

[0027] The solid sludge is dispersed in an aqueous sodium salt solution, heated, and subjected to a first solid-liquid separation to obtain a supernatant;

[0028] The pH of the supernatant is adjusted to 2-3, and the supernatant is subjected to a second solid-liquid separation to obtain a precipitate;

[0029] The precipitate is dissolved in an alkali solution, dialyzed, and dried to obtain the solid alginate.

[0030] Further preferably, the preparation method of the alginate further satisfies at least one of the following conditions:

[0031] k. The solid sludge comprises solid sludge obtained by centrifuging ordinary activated sludge or aerobic granular sludge;

[0032] l. The sodium salt comprises at least one of sodium carbonate and sodium bicarbonate;

[0033] m. The mass fraction of the aqueous sodium salt solution is 0.3%-1%;

[0034] n. The heating temperature is 70°C-90°C;

[0035] o. Each of the first solid-liquid separation and the second solid-liquid separation independently comprises centrifuging at a speed of 8000 rpm-10000 rpm for 20 min-30 min;

[0036] p. The solution used for adjusting the pH to 2-3 comprises a hydrochloric acid solution;

[0037] q. The precipitate is brown-black in color;

[0038] r. A sodium hydroxide solution is added to the precipitate until the precipitate is completely dissolved;

[0039] s. The dialysis comprises dialysis in a dialysis bag with a molecular weight cutoff of 3500 Da for at least 24 h.

[0040] Preferably, the ratio of the amount of the alginate, the amino-containing polymer, and the alcohol solvent is 1 g:(15-25) g:(150-250) mL.

[0041] The application has the following beneficial effects:

[0042] The modified alginate adsorption material of the application enhances the adsorption of Cu(II) by increasing carboxyl and amino functional groups on the surface of the alginate matrix, and the adsorption capacity of the modified alginate adsorption material for Cu(II) is twice that of the unmodified alginate. At the same time, the modified alginate adsorption material is insoluble in water, has high mechanical strength, is more stable in the adsorption system, is not easy to break, and is conducive to the recycling and reuse of the adsorbent.

[0043] In the preparation method of the application, the alginate is cross-linked and modified with a high-molecular polymer containing amino groups under the action of a cross-linking agent to prepare a modified alginate adsorption material with a three-dimensional network cavity structure, which improves the adsorption of the adsorption material for heavy metal ions, and the preparation method is simple and convenient, the production raw materials are low in price, and the method widens the road for high-value application of alginate and makes contributions to circular economy and resource utilization of sewage plants. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as limiting the scope of the application.

[0045] Figure 1 The preferred preparation process flow chart of the modified alginate adsorption material of the application;

[0046] Figure 2 The infrared spectra of the alginate material and the modified alginate adsorption material prepared in Example 1 and Example 3;

[0047] Figure 3 The SEM photos of the alginate material and the modified alginate adsorption material prepared in Example 1;

[0048] Figure 4 The adsorption kinetics curve of the modified alginate adsorption material prepared in Example 1 under different metal ion concentrations of Cu(II);

[0049] Figure 5 The performance of desorption-adsorption of Cu(II) of the modified alginate adsorption material prepared in Example 1 in 5 cycles. DETAILED DESCRIPTION

[0050] As used herein:

[0051] "comprising," "having," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises, has, includes, or contains one or more elements possesses those one or more elements but is not limited to only those elements. The term "consisting of" is intended to exclude any element not specified.

[0052] When expressing a range, a concentration, or other value or parameter either as an upper preferred value or a lower preferred value, or as a range between an upper preferred value and a lower preferred value, it is understood that every range formed by any pair of values, either of which is an upper or lower preferred value, is specifically disclosed. For example, where a range of "1-5" is disclosed, the disclosure is understood to include ranges of "1-4," "1-3," "1-2," "1-2 and 4-5," "1-3 and 5," etc. Where a range of values is described, unless otherwise stated, the range is intended to include both the upper and lower values and all integers and fractions within that range.

[0053] In these examples, unless otherwise indicated, the parts and percentages are by mass.

[0054] "Mass parts" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 2.689 g, etc. If we say that the mass parts of component A is a parts, and the mass parts of component B is b parts, it means that the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It must not be misunderstood that, unlike mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0055] "and / or" is used to indicate that one or both of the described situations can occur, for example, A and / or B includes (A and B) and (A or B).

[0056] The modified alginate-like adsorption material provided in the present application comprises: an alginate-like matrix and a functional group connected to the alginate-like matrix; the functional group comprises a carboxyl group and an amino group.

[0057] The present application realizes the combination with heavy metals by using the amino group and the carboxyl group existing on the surface of the modified adsorption material through complexation and electrostatic interaction, and achieves the effect of removing heavy metal pollutants in wastewater.

[0058] In a preferred embodiment, the modified alginate-like adsorption material has a three-dimensional reticular cavity structure, and a particle size of 200-300 nm, for example, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, or any value between 200 nm and 300 nm.

[0059] In a preferred embodiment, the alginate-like matrix comprises alginate-like material extracted from sludge. Further, the sludge comprises ordinary activated sludge or aerobic granular sludge.

[0060] The application also provides a preparation method of the modified alginate-like adsorption material, comprising:

[0061] S1, mixing raw materials comprising alginate-like, amino-containing polymer and alcohol solvent, and performing solid-liquid separation to obtain a solid product;

[0062] S2, performing cross-linking reaction of the solid product with a cross-linking agent to obtain the modified alginate-like adsorption material.

[0063] Figure 1 The preferred preparation process flow chart of the modified alginate-like adsorption material is shown in the accompanying drawings.

[0064] In a preferred embodiment, the particle size of the alginate-like in S1 is 2-20 μm, for example, 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, or any value between 2 μm and 20 μm.

[0065] In a preferred embodiment, the amino-containing polymer in S1 comprises at least one of polyethyleneimine, polyacetamide and polyacrylimine, and more preferably polyethyleneimine (PEI).

[0066] In a preferred embodiment, the alcohol solvent in S1 comprises at least one of methanol, ethanol, propanol and isopropanol.

[0067] In a preferred embodiment, the cross-linking agent in S2 comprises glutaraldehyde. The role of glutaraldehyde is to bridge between the hydroxyl group contained in the alginate-like (ALE) and the amino group in the amino-containing polymer, specifically, one end of the aldehyde group of glutaraldehyde reacts with the hydroxyl group of the alginate-like to form a carbon-oxygen single bond, and the other end of the aldehyde group reacts with the amino group of the amino-containing polymer to form a carbon-nitrogen double bond.

[0068] In a preferred embodiment, the solid-liquid separation in S1 comprises centrifugation at a speed of 5000-10000 rpm for 15-30 min, and more preferably centrifugation at a speed of 8000 rpm for 20 min.

[0069] In the process of S1, alginate is combined with amino-containing polymer by electrostatic attraction through the carboxyl group (negative charge) on the surface of alginate and the positive charge of the amino-containing polymer, and then the alginate with the electrostatically combined amino-containing polymer is obtained by solid-liquid separation. However, the electrostatic combination is not tight, and the charging condition on the surface of alginate will change with the change of pH of the solution. When the pH decreases, the electrostatic binding force between the amino-containing polymer and the alginate will decrease, causing a part of the amino-containing polymer to be released into the solution, thereby destroying the stability of the adsorbent material. Therefore, the solid product is reacted with a crosslinking agent in S2 to crosslink the hydroxyl group in the alginate and the amino group in the polymer.

[0070] In a preferred embodiment, the crosslinking reaction in S2 includes: transferring the solid product into water, adjusting the pH to 8-9, adding the crosslinking agent drop by drop, continuously stirring, and obtaining the modified alginate adsorbent material. More preferably, the crosslinking reaction is carried out at pH = 8.

[0071] Further preferably, the crosslinking agent is selected from glutaraldehyde with a mass fraction of 20%-30%, and more preferably glutaraldehyde with a mass fraction of 25%.

[0072] Further preferably, the volume ratio of water to the alcohol solvent added in S1 is 1:(0.9-1.1), and more preferably 1:1; and the volume ratio of the crosslinking agent to the water is 1:(20-30), and more preferably 1:25.

[0073] Further preferably, adjusting the pH to 8-9 includes adjusting using a sodium hydroxide solution, and more preferably adjusting using a 0.4M sodium hydroxide solution.

[0074] Further preferably, after adding the crosslinking agent, the continuous stirring is performed for 1h-2h, and more preferably 1h.

[0075] Further preferably, after the crosslinking reaction, the continuously stirred mixed solution is further centrifuged, washed, and dried to obtain the modified alginate adsorbent material.

[0076] In a preferred embodiment, the alginate in S1 is selected from alginate material extracted from sludge, and the preparation method thereof includes:

[0077] S001, dispersing solid sludge in an aqueous sodium salt solution, heating, performing first solid-liquid separation, and obtaining supernatant;

[0078] S002, adjusting the pH of the supernatant to 2-3, performing second solid-liquid separation, and obtaining precipitate;

[0079] S003, dissolving the precipitate in an alkali solution to obtain a mixed solution, dialysis, drying to obtain solid alginate.

[0080] The solid sludge of S001 includes centrifuging ordinary activated sludge or aerobic granular sludge to obtain solid sludge.

[0081] It can be understood that the sludge taken from the sewage treatment plant generally needs to be subjected to gravity sedimentation for several times, and supernatant is discharged to increase the concentration of the sludge, and then the sludge is subjected to centrifugal concentration to remove soluble impurities, and then alginate is extracted from the obtained solid sludge.

[0082] Further preferably, the sodium salt of S001 includes at least one of sodium carbonate and sodium bicarbonate, and more preferably sodium carbonate.

[0083] Further preferably, the mass fraction of the aqueous solution of the sodium salt is 0.3%-1%, and more preferably 0.5%.

[0084] Further preferably, the heating temperature is 70°C-90°C, and more preferably the heating is performed in a water bath at 80°C for 30 min.

[0085] It should be noted that the sludge suspension is extracted by using high-temperature sodium carbonate, and the principle is that alginate combined with divalent cations such as calcium and magnesium is replaced by carbonate in sodium carbonate, and then soluble sodium alginate is generated.

[0086] The first solid-liquid separation in S001 and the second solid-liquid separation in S002 each independently include centrifuging at a speed of 8000 rpm-10000 rpm for 20 min-30 min, and more preferably centrifuging at a speed of 10000 rpm for 20 min.

[0087] When the pH of the supernatant is adjusted to 2-3, and more preferably the pH is 2.2, 1M hydrochloric acid solution can be added to slowly adjust the pH, and a brown-black gel precipitate can be generated.

[0088] Further preferably, when the precipitate is dissolved in an alkali solution, the method includes slowly adding 1M sodium hydroxide solution to the precipitate to adjust the pH to 8.5 so that the precipitate is completely dissolved.

[0089] It should be noted that the supernatant containing alginate-like is added with hydrochloric acid to adjust the pH to be acidic, because alginate-like will precipitate to form brown-black alginate-like gel under acidic conditions, and the precipitation is complete at pH = 2.2; then the alginate-like gel is transferred into a sodium hydroxide solution, and under constant stirring, the alginate-like gel gradually dissolves and converts into alginate-like, and the conversion is complete at pH = 8.5 or so. The purpose of adjusting the acid and alkali is to improve the purity of the alginate-like finally extracted.

[0090] Further preferably, when the mixed solution after complete dissolution is dialyzed, it includes: placing the mixed solution in a dialysis bag of 3500 Da for dialysis for 24 h, and changing pure water every 12 h; then freezing the alginate-like solution after dialysis, and freeze-drying in a vacuum drying machine for 24 h.

[0091] It should be particularly noted that the alginate-like in the present application is in the form of sodium salt.

[0092] In a preferred embodiment, the ratio of the amount of alginate-like, amino-containing polymer and alcohol solvent in S1 is 1 g:(15-25) g:(150-250) mL, and more preferably 1 g:20 g:200 mL.

[0093] The embodiments of the present application will be described in detail below with specific examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0094] Example 1

[0095] The present application provides a modified alginate-like adsorption material, and a specific preparation method thereof includes:

[0096] 1. Extraction of alginate-like:

[0097] 1) Take 150 ml of residual sludge (ordinary activated sludge) from Dongba Sewage Plant and centrifuge at 10000 rpm for 20 min, remove the supernatant, and retain the solid below;

[0098] 2) Add 1 g of Na2CO3 solid to the remaining solid, and then dilute to 200 mL with pure water;

[0099] 3) The mixed solution after constant volume is heated in a water bath at 80°C for 30 min;

[0100] 4) Centrifuge at 10000 rpm for 20 min, and retain the supernatant;

[0101] 5) Slowly titrate the supernatant with 1.0M HCl solution to adjust pH = 2.2, and brown-black gel can be observed;

[0102] 6) Centrifuge at 10000 rpm for 20 min, remove the supernatant, collect the gel precipitate, and then slowly adjust pH = 8.5 with 1.0M NaOH solution until the gel is completely dissolved;

[0103] 7) The dissolved solution is placed in a 3500 Da dialysis bag and dialyzed for 24h, and the pure water is replaced every 12h;

[0104] 8) After the dialysis of the alginate-like solution is completed, freeze-drying in a vacuum drying machine for 24h to obtain alginate-like solid.

[0105] 2. Preparation of adsorbent material:

[0106] 1) 0.5g of freeze-dried alginate-like solid is placed in 100ml of methanol solution, stirred with a magnetic rotor to disperse uniformly, and then 10g of polyethyleneimine is slowly transferred to the system by a glass rod, and continuously stirred for 24h to make the alginate and polyethyleneimine fully react;

[0107] 2) After stirring, centrifuge at 8000 rpm for 20 min to remove the residual polyethyleneimine in the supernatant and retain the solid;

[0108] 3) The solid is transferred to 100mL of pure water, 4mL of 25wt% glutaraldehyde is added dropwise, and the pH of the mixture is adjusted to 8 with 0.4M NaOH, and then stirred for 1h to make the polyethyleneimine and alginate fully crosslinked;

[0109] 4) After centrifugation at 8000 rpm for 20 min, remove the supernatant and retain the solid, which is the crosslinked product;

[0110] 5) The crosslinked product is washed with pure water for 3 times, frozen and freeze-dried in a vacuum drying machine for 24h, and finally the solid is ground into powder to obtain the modified alginate-like adsorbent material.

[0111] The maximum adsorption capacity of the modified alginate-like adsorbent material prepared in this example for Cu(II) is 98.01mg / g.

[0112] Example 2

[0113] This example provides a modified alginate-like adsorbent material, and the specific preparation method is the same as that of Example 1, except that in the extraction process of alginate-like, the ordinary activated sludge of Xiaohongmen Sewage Plant is selected in step 1).

[0114] The maximum adsorption amount of the modified alginate-like adsorption material prepared in the embodiment to Cu(II) is 79.29 mg / g.

[0115] Example 3

[0116] The embodiment provides a modified alginate-like adsorption material, and a specific preparation method is same to that in Example 1, except that in the extraction process of the alginate-like material, the aerobic granular sludge of Nanyang sewage plant is selected in step 1).

[0117] The maximum adsorption amount of the modified alginate-like adsorption material prepared in the embodiment to Cu(II) is 83.46 mg / g.

[0118] Comparative Example 1

[0119] The comparative example provides an alginate-like adsorption material without modification, and a preparation method is same to the extraction process of the alginate-like material in Example 1. The maximum adsorption amount of the alginate-like adsorption material prepared in the comparative example to Cu(II) is 40 mg / g.

[0120] Figure 2 The infrared spectrograms of the alginate-like material and the modified alginate-like adsorption material in Example 1 and Example 3 are given. In the infrared spectrograms, Figure 2 (a) in the infrared spectrograms is the infrared spectrogram of the alginate-like material (ALEC1) and the modified alginate-like adsorption material (ALEC1-PEI) prepared in Example 1; Figure 2 (b) in the infrared spectrograms is the infrared spectrogram of the alginate-like material (ALEA) and the modified alginate-like adsorption material (ALEA-PEI) prepared in Example 3. It can be seen from the infrared spectrograms that: Figure 2 the infrared spectrograms of the two are similar, and the modified alginate-like adsorption material has an absorption peak at 1400 cm-1, corresponding to the symmetric stretching vibration of COO, indicating the existence of hydroxyl; the stretching vibration of-CH2- at 2925 cm-1, 2854 cm-1, the deformation vibration shift at 1452 cm-1 and the sharp increase of the N-H bending vibration absorption peak at 1650 cm-1 all indicate that the polyethyleneimine is successfully grafted onto the alginate-like material. -1 -1 -1 -1 -1

[0121] Figure 3 The SEM photos of the alginate-like material and the modified alginate-like adsorption material prepared in Example 1 are given. In the SEM photos, Figure 3 (a) and (c) in the SEM photos respectively represent the low-magnification SEM photo and the high-magnification SEM photo of the alginate-like material (ALEC1) prepared in Example 1; Figure 3 ​​​​​(b), (d) in FIG. 1 represent the high-magnification SEM images of the modified alginate-like adsorbent material (ALEC1-PEI) prepared in Example 1. After the cross-linking modification, the formation of three-dimensional reticular cavity structure can be observed from the SEM images of the modified alginate-like adsorbent material of Example 1.

[0122] Figure 4 FIG. 4 represents the adsorption kinetics curves of the modified alginate-like adsorbent material (ALEC1-PEI) prepared in Example 1 under different metal ion concentrations (25 mg / L, 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 300 mg / L) of Cu(II).

[0123] Figure 5 FIG. 5 represents the desorption-adsorption performance of Cu(II) of the modified alginate-like adsorbent material (ALEC1-PEI) prepared in Example 1 in 5 cycles. It can be seen from the figure that the adsorption of Cu(II) is decreased in the second cycle, but the adsorption of Cu(II) remains stable in the subsequent cycles.

[0124] Table 1 is the elemental analysis results of the modified alginate-like adsorbent material (ALEC1-PEI) prepared in Example 1, in which the higher N element content proves that the polyethyleneimine is successfully introduced into the alginate-like system.

[0125] Table 1 Elemental analysis of the modified alginate-like adsorbent material of Example 1

[0126] Element Mass ratio (%) C 72.10±6.85 N 15.60±2.36 O 11.40±1.55 P 0.70±0.03 Cu 0.20±0.08

[0127] Table 2 Specific surface area of the alginate-like materials of Examples 1-3 before and after modification

[0128]

[0129] Table 2 represents the specific surface area changes of the alginate-like materials prepared in Examples 1-3 before and after the cross-linking modification with polyethyleneimine. It can be seen that after the cross-linking modification, the specific surface area of ALEC1 increases the most, followed by ALEA and ALEC2.

[0130] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0131] Furthermore, to the extent that the terms "comprises", "comprising", "includes", "including" and "has" or any variation thereof are used in the specification and / or claims, these terms are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, includes or has a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. In addition, to the extent that the terms "coupled", "coupling", "connected", "connecting" or "connection" are used in the specification and / or claims, these terms are intended to refer to either a direct connection between entities that are in physical or logical contact with each other or an indirect connection through one or more intermediate entities.

Claims

1. A modified alginate-like adsorbent material, characterized in that, include: Alginate matrix and functional groups attached to the alginate matrix; The functional groups include carboxyl and amino groups; The modified alginate adsorbent material has a three-dimensional network cavity structure; The preparation method of the modified alginate adsorbent material includes: The raw materials, including alginate, amino-containing polymers and alcohol solvents, are mixed and then separated into solid and liquid components to obtain a solid product. The solid product is subjected to a crosslinking reaction with a crosslinking agent to obtain the modified alginate adsorbent material; The crosslinking reaction includes: transferring the solid product into water, adjusting the pH to 8-9, adding the crosslinking agent dropwise, and continuously stirring to obtain the modified alginate adsorbent material.

2. The modified alginate adsorbent material as described in claim 1, characterized in that, The modified alginate adsorbent material has a particle size of 200nm-300nm.

3. The modified alginate adsorbent material as described in claim 1, characterized in that, The alginate matrix comprises alginate materials extracted from sludge.

4. The modified alginate adsorbent material as described in claim 1, characterized in that, At least one of the following conditions must be met: a. The particle size of the alginate is 2μm-20μm; b. The amino-containing polymer includes at least one of polyethyleneimine, polyacetamide, and polypropyleneimine; c. The alcohol solvent includes at least one of methanol, ethanol, propanol, and isopropanol; d. The crosslinking agent includes glutaraldehyde; e. The solid-liquid separation includes centrifugation at a speed of 5000 rpm to 10000 rpm for 15 min to 30 min.

5. The modified alginate adsorbent material as described in claim 1, characterized in that, The crosslinking reaction also satisfies at least one of the following conditions: f. The crosslinking agent is selected as glutaraldehyde with a mass fraction of 20%-30%; g. The volume ratio of the water to the alcohol solvent is 1:(0.9-1.1), and the volume ratio of the crosslinking agent to the water is 1:(20-30). h. The adjustment of pH to 8-9 includes: using a sodium hydroxide solution for adjustment; i. The continuous stirring time is 1-2 hours; j. After the crosslinking reaction is completed, the process further includes: centrifuging, washing, and drying the continuously stirred mixed solution to obtain the modified alginate adsorbent material.

6. The modified alginate adsorbent material as described in claim 1, characterized in that, The preparation method of the alginate includes: Solid sludge is dispersed in an aqueous solution of sodium salt, heated, and subjected to the first solid-liquid separation to obtain supernatant; The pH of the supernatant was adjusted to 2-3, and a second solid-liquid separation was performed to obtain the precipitate; The precipitate was dissolved in an alkaline solution, dialyzed, and dried to obtain the solid alginate.

7. The modified alginate adsorbent material as described in claim 6, characterized in that, The method for preparing the alginate also satisfies at least one of the following conditions: k. The solid sludge includes solid sludge material obtained by centrifuging ordinary activated sludge or aerobic granular sludge; l. The sodium salt includes at least one of sodium carbonate and sodium bicarbonate; m. The mass fraction of the aqueous solution of the sodium salt is 0.3%-1%; n. The heating temperature is 70℃-90℃; o. The first solid-liquid separation and the second solid-liquid separation each independently include: centrifugation at a speed of 8000rpm-10000rpm for 20min-30min; p. The solution used to adjust the pH to 2-3 includes hydrochloric acid solution; q. The precipitate is brownish-black in color; r. The process of dissolving in alkaline solution includes: adding sodium hydroxide solution to the precipitate until the precipitate is completely dissolved; s. The dialysis consists of: dialysis in a 3500 Da dialysis bag for at least 24 hours.

8. The modified alginate adsorbent material according to any one of claims 1-7, characterized in that, The ratio of the amount of the alginate, the amino-containing polymer, and the alcohol solvent is 1 g: (15-25) g: (150-250) mL.

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